1. Division of Gastroenterology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
2. Department of Clinical Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
3. Division of Gastroenterology, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
4. Division of Gastroenterology, The First Affiliated Hospital, Sun Yat-Sen University, No. 58 Zhongshan Road 2, Guangzhou 510080, China